Extension of the hydrophobic W1 peptide with a polycationic programmed cell death‐inducing sequence, D‐(KLAKLAK)2, enabled GRP78‐dependent cell uptake and apoptosis within the DU145 cells, leading to tumor growth inhibition in a xenograft prostate cancer model, underscoring its potential therapeutic utility [19]. This evidence concerns the gene HSPA5 and prostate cancer.